Spinal implant surgery may be performed by a posterior lumbar interbody fusion (PLIF) approach, a transforaminal lumbar interbody fusion (TLIF) approach, or an extreme lateral interbody fusion (XLIF) approach. In these procedures, implants are inserted in desired positions in relation to the spine. Current spinal implant designs require an end approach deployment mechanism that is not satisfactory for certain procedures. For example, with scoliosis in the thoracolumbar spine, an orthogonal approach is often not possible. Additionally, with TLIF approaches utilizing expandable implants, the deployment has to be performed after the implant, e.g., cage or intervertebral spacer, has been turned inside the disk space. This prevents access to adjust the height of the implant after the implant has been turned, and makes extraction or removal problematic.
Current expandable implant designs are limited to PLIF type of approaches because the implants cannot be turned or collapsed. However, with PLIF approaches, there may be a risk that the expanded implant or cage extrudes back into the nerves of the spinal canal along the direction of its original insertion. In contrast, when a spacer is inserted with a TLIF approach, it is turned such that the trajectory is along the wide axis (side-to-side) of the vertebral body and the implant cannot migrate out backwards into the spinal canal.